telescopecomparison · 2-way
TS-Optics UNC 254 f/4 Newtonian Astrograph vs Astro-Physics 190mm f/6 StarFire CS
TS-Optics
UNC 254 f/4 Newtonian Astrograph
Best suited for intermediate imagers building a versatile kit running a permanent observatory setup.
Astro-Physics
190mm f/6 StarFire CS
Best suited for intermediate imagers building a versatile kit running a permanent observatory setup.
Key differences
-11% focal length
+34% aperture
Faster by 2.0 f-stops
Specifications
| Specification | TS-Optics UNC 254 f/4 Newtonian Astrograph | Astro-Physics 190mm f/6 StarFire CS |
|---|---|---|
| Optics | ||
| Type | newtonian | refractor |
| Optical design | Newtonian astrograph | Christen Superachromat (4-element) |
| Aperture | 254mm | 190mm |
| Focal length | 1016mm | 1140mm |
| Native f/ratio | f/4.0 | f/6.0 |
| Image circle | — | 64mm |
| Full-frame support | Yes | Yes |
| Physical | ||
| Weight | 14.0kg | 17.7kg |
Advantages of TS-Optics UNC 254 f/4 Newtonian Astrograph
- Wider field — 1016mm vs 1140mm focal length
- 34% more light-gathering aperture
- Faster optics at f/4 vs f/6
- Lighter (14kg vs 17.7kg) — easier to travel with
Advantages of Astro-Physics 190mm f/6 StarFire CS
- Tighter framing — 1140mm vs 1016mm focal length
- Larger image circle (64mm) — supports bigger sensors
Best for — TS-Optics UNC 254 f/4 Newtonian Astrograph
- Medium-sized galaxies and planetary nebulae
- Fast imaging — short exposures per sub
- Faint-object imaging under dark skies
- Full-frame astro cameras and DSLRs
Best for — Astro-Physics 190mm f/6 StarFire CS
- Medium-sized galaxies and planetary nebulae
- Full-frame astro cameras and DSLRs
TS-Optics UNC 254 f/4 Newtonian Astrograph — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 2.03° × 1.35°Scale: 0.76"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 1.33° × 0.89°Scale: 0.76"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 0.64° × 0.64°Scale: 0.76"/px
Astro-Physics 190mm f/6 StarFire CS — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 1.81° × 1.21°Scale: 0.68"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 1.18° × 0.79°Scale: 0.68"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 0.57° × 0.57°Scale: 0.68"/px
TS-Optics UNC 254 f/4 Newtonian Astrograph — recommended user
Best suited for intermediate imagers building a versatile kit running a permanent observatory setup.
Astro-Physics 190mm f/6 StarFire CS — recommended user
Best suited for intermediate imagers building a versatile kit running a permanent observatory setup.
